CENTRAL ELECTRICITY REGULATORY …Order in Petition No. 249/250/251/MP/2012 Page 1 of 29 CENTRAL ELECTRICITY REGULATORY COMMISSION NEW DELHI Petition No. 249/MP/2012 Coram: Shri V.S.Verma,

------------------------------------------------------------------------------------------------------------------------------- Order in Petition No. 249/250/251/MP/2012 Page 1 of 29

CENTRAL ELECTRICITY REGULATORY COMMISSION NEW DELHI

Petition No. 249/MP/2012

Coram:

Shri V.S.Verma, Member Shri M.Deena Dayalan, Member

Date of Hearing: 07.03.2013 Date of Order: 19.12.2013

In the matter of:

Maintaining security of the inter-connected power system of India in terms of Regulation 5.2 of the Central Electricity Regulatory Commission (Indian Electricity Grid Code) Regulations, 2010 and compliance of Regulations 5.4.2 and 6.4.8 of the Grid Code read along with Regulation 111 of the Central Electricity Regulatory Commission (Conduct of Business) Regulations, 1999.

And

In the matter of: Northern Regional Load Despatch Centre, 18-A, Qutub Institutional Area, New Delhi- 110016

…..Petitioner Vs

1. Punjab State Transmission Corporation Limited The Mall, Patiala-147001 2. Haryana Vidyut Prasaran Nigam Limited Shakti Bhawan, Sector-6, Panchkula- 134109

3. Rajasthan Rajya Vidyut Prasaran Nigam Limited Vidyut Bhawan, Janpath, Jaipur- 302005

4. Delhi Transco Limited SLDC Building, 2nd Floor, 33 kV Sub-station, Tagore Road, Minto Road, New Delhi- 110002


5. Uttar Pradesh Power Transmission Corporation Limited Shakti Bhawan, 14,Ashok Marg, Kuknow- 226007

6. Himachal Pradesh State Electricity Board Vidyut Bhawan, Kumar House Complex Building-II, Shimla- 171002

7. Power Transmission Corporation Limited of Uttarakhand Limited 7-B, Lane-1, Vasant Vihar Enclave, Dehradun

8. Power Development Department Grid Substation Complex Janipur, Jammu.

9. Electricity Department, Sector 9-D, UT Chandigarh- 160019

10. The Chief Electricity Distribution Engineer, North Central Railways, Allahabad.

11. State Load Despatch Centre, SLDC Complex, Near 220 kV, Grid Station, Ablowal, Patiala- 147001. 12. State Load Despatch Centre, Haryana Vidyut Prasaran Nigam Limited Shakti Bhawan, Sector- 6, Dist- Ambala, Panchkula, Haryana- 134109. 13. State Load Despatch Centre, Vidyut Bhawan, Janpath, Jaipur- 302005.

14. The General Manager SLDC Delhi Transco Limited, SLDC Building, 2nd floor,

33 kV s/s, Tagore Road, Minto Road, New Delhi- 110002

15. State Load Despatch Centre, Energy System, 5th Floor, Shakti Bhawan, Ashok Marg,Lucknow- 226007. 16. State Load Despatch Centre, PTCUL, 400 kV s/s, SLDC, Virbhadra, Rishikesh -249202

17. State Load Despatch Centre Himachal Pradesh State Electricity Board, SLDC Control Centre, HPSEB, Totu Shimla, Himachal Pradesh- 171101


18. State Load Despatch Centre Power Development Department, SLDC Building, Narwalbala, Gladini, Jammu – 180016. …….Respondents

Petition No. 250/MP/2012

In the matter of:

Maintaining security of the interconnected power system of India in terms of Regulation 5.2 of the Central Electricity Regulatory Commission (Indian Electricity Grid Code) Regulations, 2010 and compliance of Regulations 5.4.2 and 6.4.8 of the Grid Code read along with Regulation 111 of the Central Electricity Regulatory Commission (Conduct of Business) Regulations, 1999.

And

In the matter of: Southern Regional Load Despatch Centre, Power System Operation Corporation Limited, 29, Race Course Cross Road, Benguluru- 560009, Karnataka …..Petitioner

Vs 1. Chairman and Managing Director APTRANSCO, Viyut Soudha, Hyderabad- 500082 2. Managing Director,KPTCL, Cauvery Bhavan, Bangalore- 560009, Karnataka 3. Chairman, KSEB, Vaidyuthi Bhavanm, Pattom, Trivandrum- 695004, Kerala 4. Chairman, TANTRANSCO, 144, Anna Salai, Chennai- 600002, Tamil Nadu 5. Electricity Department, Govt. of Puducherry, No. 137, Netaji Subhash Chandra Bose Salai, Pondicherry - 605 001 …….Respondents


Petition No. 251/MP/2012 In the matter of:

Maintaining security of the interconnected power system of India in terms of

Regulation 5.2 of the Central Electricity Regulatory Commission (Indian Electricity

Grid Code) Regulations, 2010 and compliance of Regulations 5.4.2 and 6.4.8 of

the Grid Code read along with Regulation 111 of the Central Electricity Regulatory

Commission (Conduct of Business) Regulations, 1999.

And

In the matter of: Eastern Regional Load Despatch Centre, 14, Golf Club Road, Tollygunge,Kolkata-700033 (W.B) …..Petitioner

Vs 1. Managing Director West Bengal State Electricity Transmission Company Limited, Bidyut Bhawan, 7th Floor, Block DJ, Sector-II, Bidhannagar, Kolkata-700 091 2. Chairman Bihar State Electricity Board, Vidyut Bhawan, Bailey Road, Patna-800 021 3. Chairman Jharkhand State Electricity Board, Engineering Bldg, HEC, Dhurwa, Ranchi-834 004

4. Chairman Damodar Valley Corporation, DVC Tower, Maniktala, Civic Tower, VIP Road, Kolkata-700 054

4. Chairman, Orissa Power Transmission Corporation Limited, Janpath, Bhubaneshwar- 751022.

5. Power Department,


Govt. of Sikkim, Kazi Road, Gangtok- 737 101 6. Bihar State Electricity Board Vidyut Bhawan, Bailey Road, Patna-800 021 7. Jharkhand State Electricity Board, Kusai Colony, Doranda, Ranchi- 834002

8. Chief Engineer, CLD, DVC, P.O. , Maithon Dam, Maithon

9. Orissa Power Transmission Company Limited, P.O Mancheswar Rly. Colony, Bhubaneshwar- 751017

10. SLDC, Power Department, Govt. of Sikkim, Gangtok

11. Chief Engineer, WBSETCL, P.O. Danesh Sheikh Lane, Andul Road, Howrah- 711109. …….Respondents Following were present:

Shri V.V.Sharma, NRLDC Shri V.K.Agarwal, NRLDC Shri S.C.Saxena, NRLDC Shri S.R.Narasimhan, NRLDC Shri Rajiv Porwal, NRLDC Miss Joyti Prasad, NRLDC Shri Vivek Pandey, NRLDC Shri Naresh Kumar, NRPC Shri R.B.Sharma, Advocate, BRPL, JSEB and GRIDCO Ms. Mahima Sinha, Advocate, Karnataka Shri S.K.Jain, RRVPNL Shri Darshan Singh, SLDC, Delhi Shri R.K.Sharma, SLDC, Punjab Shri V.Suresh, SRLDC Shri S.Konar, ERLDC Shri P.Pentayya, WRLDC Shri Mahesh Kumar Shri M.K.Gupta, AE Shri K.K.Prabhakar, MPPTCL Shri Antim Jain, MPPKVVCL Shri Sanjay Bhagwatka Shri P.Rajaguanidhi, TANTRANSCO Shri Vikas Sharma, J&K, PDD


Shri Zahir Ahmad, SLDC,UP Shri Avijeet Lala, Advocate, SLDC, WBSETCL Shri A.Biswas, SLDC, WBSETCL Shri P.P.Biswas, WBSETCL

Order

The petitioners, Northern Regional Load Despatch Centre, Southern

Regional Load Despatch Centre and Eastern Regional Load Despatch Centre

have filed these petitions with the following prayers:

"(a) Direct all the STUs/SLDCs to forecast their demand and make adequate arrangements to avoid dependence on Unscheduled Interchange for meeting their demand or for injecting short term surplus power, irrespective of the frequency; (b) Direct all the STUs/SLDCs to implement automatic demand disconnection scheme as mandated in the Regulation 5.4.2 (d) of the Grid Code and submit the details of the same to CERC/RPCs/RLDCs; (c) Direct all the STUs/SLDCs/Regional Entities to comply with Regulation 5.2 (j) of the Grid Code; (d) Direct all the STU/SLDCs to give their inputs to implement the Grid Security Expert System and direct the Regional Power Committee’s secretariat should actively associate themselves in getting these schemes implemented in terms of NLDC letter ref POSOCO/NLDC dated 11.9.2011 to Member GO&D; and (e) Pass such other order or directions as deemed fit in the circumstances of the case."

2. The facts of these cases and reliefs prayed for in these cases are similar.

Gist of the common submissions by the petitioners is as under:

(a) There was a major grid disturbance in Northern Region at 02.33 hrs

on 30.7.2012. Northern Regional Grid load was about 36,000 MW at the

time of disturbance. Subsequently, there was another grid disturbance at


13.00 hrs on 31.7.2012 resulting in collapse of Northern, Eastern and

North-Eastern regional grids. The total load of about 48,000 MW was

affected in this black out.

(b) There are large fluctuations in the grid parameters such as

frequency, voltage and line loadings on account of large changes in the

scheduled and actual drawal (>100 MW) by the State Utilities at the hour

boundary attributable to the following reasons:

(i) Manual connection/disconnection of large block of load at the

hour boundary.

(ii) Large step change in the drawal schedule due to large

change in quantum of buy/sell in Short Term Open Access at the hour

boundary/time block boundary.

(c) Regulation 5.2 (j) of Grid Code mandates that no user/SEB shall

cause a sudden variation in its load by more than 100 MW without prior

intimation and consent of the RLDC. However, typical instances of violation

of Grid Code by the State utilities are illustrated, wherein State utilities of

UP, Rajasthan, Haryana, Punjab, J&K and Delhi have changed in

overdrawal at hourly boundary frequency variation. Such large fluctuations

in the grid parameter are a threat to grid security as it may result in mis-

operation area of the protective relays and cause undesirable tripping in the


system. Therefore, the change in drawal by the utilities should be in small

steps /gradual <100 MW as mandated in Grid Code.

(d) In accordance with Regulation 5.4.2 of Grid Code,

SLDC/SEB/distribution licensee and bulk consumer are required to ensure

that requisite load shedding is carried out in its control areas so that there is

no overdrawal when frequency is 49.7 Hz or below. It has been observed

that that the overdrawal by certain regional entities is very large when the

frequency is 49.8-50.2 Hz. Under these conditions, if there is a contingency

(such as loss of generating units), the system frequency would rapidly fall to

insecure level in the absence of automatic control actions.

(e) Regulation 6.4.2 (a) of the Grid Code mandates that the

SLDC/SEB/distribution licensee and bulk consumer shall initiate action to

restrict overdrawal of its control area, from the grid, whenever the frequency

falls to 49.8 Hz.

(f) Regulation 6.4.8 of the Grid Code mandates that the

SLDCS/STUs/Distribution Licensees shall regularly carry out demand

estimation for their respective States/area, to enable them to plan in advance

as to how they would meet their consumers load without overdrawing from

the grid.


(g) In view of the circumstances elaborated above, the petitioners have

been taking the following actions in the interest of grid security:

(i) Directing the regional entities to maintain their drawal/injection

as per the schedule even when the grid frequency is within the band

of 49.8-50.2 Hz;

(ii) Issuing verbal/written messages and SMS to the concerned

authorities for suitable intervention in maintaining grid discipline

and/or take corrective actions during contingencies;

(iii) Issuing A, B and C Messages for persistent and large

quantum of Unscheduled Interchange from the grid;

(iv) Carrying out suo-motu revisions in the schedule under

perceived threat to grid security ; and

(v) Physical disconnection of EHV feeders in case of persistent

overdrawal/indiscipline or delay in response from the utilities.

(h) CTU has prepared a draft proposal for ‘Grid Security Expert System’

(GSES). The GSES envisages the following:

(i) Remote demand disconnection from the SLDC / RLDC;

(ii) Real-time assessment of the quantum of load relief available

through safety net; and


(iii) Supervision of healthiness of the safety net (UFRLS, UVLS,

df/dt LS) from remote.

(iv) GSES cut down the response time during emergencies which

would also enable the grid operators to assess the security margins

required to be maintained in the system. NLDC has given its technical

inputs vide its letter ref POSOCO/NLDC dated 11.9.2011 to Member

(GO & D), CEA. Inputs have been sought from the State utilities and

RPCs on the following aspects:

(i) Identification of feeders for the automatic demand

disconnection; and

(ii) Updated list of feeders installed with under frequency/under

voltage, df/dt relays.

3. The Commission vide its order dated 14.1.2013 directed the Regional

Power Committee of all regions to discuss the issue of 'implementation of the

Automatic Demand Management Scheme at the SLDC/distribution company level'

as an agenda item within one month and file decisions on affidavit within one

week thereafter after serving the copies thereof on all the constituents of the

respective RPC. The Commission further directed to all distribution licensees to

participate in the respective RPC meetings and SLDCs were directed to provide all

necessary data and assistance to NLDC and respective RLDCs for effective


implementation of the Automatic Demand Management Scheme. The Commission

further directed all SLDCs and distribution companies to strictly comply with the

provisions of the Grid Code and directions of respective RLDCs to maintain grid

discipline. RLDCs were directed to take necessary actions in accordance with the

provisions of the Electricity Act, 2003 and the Grid Code including disconnection

of feeders, wherever necessary, from the point of view of grid security.

4. Replies to the petitions have been filed by Delhi Transco Limited, Rajasthan

Rajya Vidyut Prasaran Nigam Ltd, Punjab State Power Corporation Ltd,

Transmission Corporation of Andhra Pradesh Limited (APTRANSCO), Tamil Nadu

Transmission Corporation Limited (TANTRANSCO), Kerala State Electricity Board

(KSEB), Karnataka Power Transmission Corporation Limited (KPTCL), Northern

Regional Power Committee (NRPC), Southern Regional Power Committee

(SRPC), Southern Regional Load Despatch Centre (SRLDC) and Grid Security

Expert System (GSES).

5. Delhi Transco Limited vide its affidavit dated 26.12.2012 has submitted as

under:

(a) As far as Delhi system is concerned, no manual connection and

disconnection of load occurred. However, these changes are due to natural

load occurring in the system during peak hours particularly during winter

months.


(b) The response of Under Frequency Relays (UFR) during the time of

Grid disturbance were adequate in Delhi System and same has already

been submitted in Petition No. 221/MP/2012. Though the existing static

UFR are functioning satisfactorily, for quick response all these relays are

proposed to be replaced with State-of-the-Art.

(c) The contention of the petitioner that in the event of disconnection of

feeders from Grid Sub-station may affect important loads, though is correct,

but in case of exigencies, this has to be done in any case as the same is

applicable in case of SLDC or STU does load shedding from their sub-

stations.

(d) The proposal of Grid Security Expert System (GSES) was put up in

the 25th NRPC meeting held on 30.11.2012 wherein there was a general

consensus that the proposed system should be implemented subject to

feasibility. DTL has no other opinion and would try to implement in

coordination with other utilities as and when proposal is cleared by Central

Electricity Authority or RPC Forum.

6. Rajasthan Rajya Vidyut Prasaran Nigam Ltd (RVPNL) vide its affidavit

dated 4.1.2013 has submitted that Rajasthan is complying the directions of

NRLDC and provided details of relief and details of feeders disconnected and


messages received from NRLDC. RVPNL has requested to provide to Distribution

Company/ STU/SLDC the full GSES scheme for thorough studies so that input

may be provided to CTU.

7. Punjab State Power Corporation Ltd. (PSPCL) vide its affidavit dated

27.12.2013 has submitted as under:-

(a) PSPCL has confirmed having forecast their demand and made

arrangements to meet the demand without any dependence of UI for the year

2012-13 (up to 31.10.2013). PSPCL have further undertaken that real time

shortage if any will be met by purchase of power from exchange on day ahead

basis or by imposition of Regulatory measures.

(b) SLDC, Punjab has also filed Petition No. 49/2012 before Punjab State

Electricity Regulatory Commission seeking directions to PSPCL for

implementation of automatic demand disconnection scheme in its control area

for maintaining voltage and frequency profile, in line with provisions of the Grid

Code.

(c) Grid Security Expert System (GSES) as a unified scheme for all

constituents, was discussed in the NRPC meeting held on 29th, 30th

November, 2012. Power Grid is to explain the said scheme to the constituents

before taking up its further development/implementation. Necessary basis


inputs for disconnection of feeders have since been supplied to NRLDC during

the meeting held on 7.8.2012.

8. Transmission Corporation of Andhra Pradesh Limited (APRTRANSCO) vide

its affidavit dated 11.12.2012 has submitted as under:-

(a) With regard to violation of Regulation 5.2 (j) of the Grid Code on

sudden variation of 100 MW without prior intimation and consent, CEA

manual on transmission planning defined rare contingencies as temporary

removal of complete generating station or complete substation (including all

the incoming and outgoing feeders and transformers) from service, HVDC

bi-pole and stuck breaker condition.

(b) Regarding variation of frequency, it was clarified to SRLDC that the

actual relief realized was around 50% on average and the mismatch is due

to non availability of SCADA data on 132 kV level on some of the feeders in

the above load shedding scheme. The system frequency has not fallen

below 48.80 HZ (stage 1 UFR conditions) even when there is a loss of

around 2200 MW due to a grid disturbance in Karnataka on 3.4.2012

indicated by SRLDC in Annexure-1 of the petition.

(c) SRLDC is insisting adherence to 12% or 150 MW over drawls even

in high frequency conditions and is opening the ICTs between CTU and

STU even though the over drawls are not abnormal. The Commission may


consider to enhance this limit to a higher level say 250 MW in case of high

frequency, whenever transmission contingencies are not there. This will

help in optimal usage of Hydel resources.

(d) SLDC, AP formulated and implemented the Automatic Load

Management Scheme in accordance with Regulation 5.4.2 (d) of the Grid

Code, by identifying 132 kV loads, 132/33 kV transformers for a quantum of

800 MW for remote tripping from SLDC.

(e) Regarding inadequate response of thermal/hydel units, such

response is low due to lower value of the GCV than the designed GCV

during low frequency occurrences

9. Tamil Nadu Transmission Corporation Limited (TANTRANSCO) vide its

affidavit dated 12.12.2012 has submitted as under:

(a) SRPC is periodically reviewing the SR Grid parameters in monthly

Operation Coordination Committee (OCC) meeting, Technical Coordination

Committee meeting and other special meetings conveyed frequently for any

special event of the Grid. As such, petition filed by SRLDC seeking direction

to SRPC to associate the SLDCs in getting the Grid Security Expert System

implement, is unwarranted.


(b) After the major Grid collapse, SRLDC has implemented so many

stringent measures as prescribed by High Power Committee to curb

overdraw even at high frequencies and is now not allowing overdrawl by

more than 150 MW from the Grid even when the Regional Grid frequency is

above 50 Hz, which is allowable as per the provisions of Grid Code.

(c) TANTRANSCO is regularly forecasting the demand day wise / block

wise without depending on Unscheduled Interchange, and necessary

arrangements are also being made in advance based upon the availability

to meet the demand forecasted to avoid dependence on Unscheduled

Interchange.

(d) Automatic load disconnection scheme under Regulatory measures

for a quantum of 657 MW has already been implemented by

TANTRANSCO from October, 2010. The loads are being tripped as and

when necessary, generating automatic pulse through SCADA.

(e) TANTRASCO is intimating to Southern Regional Load Despatch

Centre if any variation in loads occurs. Therefore, TANTRANSCO assures

that threat to Grid security due to large fluctuations in the grid parameters

which may result in mis-operation of the protective relays and causing

undesirable tripping in the system will not happen.


(f) The Regulation stipulates conditions only for the over drawal

irrespective of frequency in view of Grid security. The continuous under

drawal in high frequency will also lead excursion in frequency which will

also be a threat to Grid security. Therefore, violation messages are also to

be issued for the conditions of under drawal at frequency above 50 Hz

which leads to over drawal of other constituents due to natural balancing.

(g) CEA may be requested to intervene in the ATC computing

procedures and ensure the accuracy and transparency of the same in view

of critical power position prevailing in Southern Region. In view of the

reasons and circumstances stated above, the present petition may be

rejected.

10. Kerala State Electricity Board vide its affidavit dated 18.1.2013 has

submitted that the Southern constituents are facing severe power shortage and

are impeding power cut and road shedding for many hours a day. However,

Eastern Region and Western Region have huge surplus power. However, due to

transmission constraints, SRLDC has denied open access to transmit power from

other regions. The present power crisis and Grid security in the Southern Region

can be relieved if sufficient transmission capacity is available for transfer of power

from Western Region and Eastern Region to Southern Region.


11. Karnataka Power Transmission Corporation Limited (KPTCL) vide its

affidavit dated 7.1.2013 has submitted as under:

(a) All the constituents in the Southern Region are cooperating to

maintain the grid discipline and aiding the integrated grid operation under

the guidance and supervision of SRLDC.

(b) KPTCL is complying with the directions of SRLDC to maintain the

grid discipline. SRLDC has also appreciated the efforts of KPTCL for

excellent and sustained grid operations in the various forums such as OCC,

TCC, SRPC meetings.

(c) SLDC, Karnataka is handling approximately 7500-8500 MW and

all efforts are being made for balancing of demand and supply. As per the

Government of Karnataka directions, measures are being taken to supply

6 hours to 3 phase supply and 12 hours of single phase supply to all rural

feeders and 22-24 hours power supply to urban and city feeders.

(d) With regard to contingency procedures, most of them do not

concern with SLDC, Karnataka at all. However, as far as the contingency

measures are concerned, the implementation of UFR scheme, df/dt

schemes and special protection load management scheme has already

been implemented from July 2012.

(e) SCADA system to all generating stations, sub-stations has fully

implemented in which feeders up to 11 kV, IPPs, NCE and solar units are


covered. Based on the said SCADA, SLDC is monitoring the grid on real

time for smooth functioning of grid operation with causing any disturbances

in the system.

12. Northern Regional Power Committee in its submission dated 1.3.2013 has

submitted that in the meeting held on 17.1.2013 and 7.2.2013 in NRPC, both

Automatic Demand Management Scheme (ADMS) as mandated in the Grid Code

Regulation 5.4.2 (d) as well as Grid Security Expert System (GSES) were

discussed. As per Minutes of Meeting (MoM) issued by NRPC following is the

status of Automatic Demand Management Scheme (ADMS) in NR:

(i) Delhi: Automatic Demand Management has been implemented;

(ii) Haryana: Distribution companies of Haryana are in the process of

installing their SCADA system. The issue of Automatic Demand

Management System is under discussion between SLDC and Discoms;

(iii) Punjab: The issue is under preliminary discussion between PSTCL and

PSPCL;

(iv) Rajasthan: A Committee has been constituted in Rajasthan for

Automatic Demand Management;

(v) Uttar Pradesh: SLDC, UP has advised distribution companies to

set up their own control rooms for Automatic Demand Management.


In Noida, Noida Power Company has established the control room

and automatic demand Management System is in place;

(vi) Uttarakhand: Draft scheme for Automatic Demand Management

Scheme has been formulated by SLDC and certain information has

been sought from distribution licensee, namely UPCL;

(vii) Jammu and Kashmir: Information has not been submitted to NRPC

Secretariat;

(viii) Chandigarh: Information has not been submitted to NRPC

Secretariat.

13. Southern Regional Power Committee (SRPC) vide its affidavit dated

26.12.2012 has submitted as under:

(a) As part of the agenda for the 76th OCC meeting held on 11.10.2012,

SRLDC had submitted 10 Templates for automated defense plan for

secure operation of grids.

(b) In the Northern Region, the matter regarding Grid Security Expert

System has been discussed in detail through an agenda item of Power

Grid. However, in Southern Region neither SRLDC nor Power Grid have

submitted any agenda item regarding Grid Security Expert System for

discussion in the OCC or Protection Sub-Committee meetings.


(c) The recommendations of the Enquiry Committee set up by the

Ministry of Power to investigate the grid disturbances in NEW GRID are

under implementation. Periodic meetings in this regard are being taken by

CEA to oversee the progress of the implementation.

(d) In the 20th SRPC Meeting held on 28.9.2012, a scheme for Unified

Real Time Dynamic Measurement Scheme was approved by SRPC. New

PABX with advance functionality to Control Centers of Southern Region for

Hot Line Communication System was also approved.

(e) The Commission may direct SRLDC/Power Grid to submit the

Agenda item for Grid Security Expert System to the SRPC forum for

discussion / approval. The 21st meeting of SRPC is scheduled to be held on

2.2.2013. SRLDC may approach the Commission in this regard in case of

non approval by the constituents in the SRPC forum.

14. SRPC vide its affidavit dated 15.2.2013 has further submitted as under:

(a) Automatic Demand Management Scheme was discussed in SRPC

meeting held on 11th & 12th February, 2013 and observations regarding UFR

relief are as under:-

(i) SRLDC was continuously monitoring all feeders connected with

AUFR and df/dt protection. SRLDC had also observed that the extent of


protection available was not adequate to ensure safe and secure grid

operation.

(ii) APTRANSCO had stated that there was no RTU coverage in respect

of certain feeders and it had increased the number of UFR feeders by

approximately 300 MW which will be confirmed implementation in about a

month's time.

(iii) TANTRANSCO had stated that all the AUFRs in the State were

operating properly and periodic testing was also being done. However, due

to heavy amount of load shedding being carried out in the State, the desired

number of feeders was not available for AUFR operation.

(iv) APTRANSCO had pointed out that during the grid disturbance in

NEW Grid on 30.7.2012, all the SLDCs in Southern Region had taken

prompt action to prevent any further decay in the frequency.

(v) KSEB had stated that the average percentage availability figures in

respect of Kerala system was of the order of 67.57% (average) with

minimum and maximum availability of 45.2% & 86% respectively, with the

present loading pattern.


(vi) KPTCL had submitted that the percentage availability in its system

was the highest amongst all the States in the Region.

(b) SRPC has placed on record the decisions of Technical Coordination

Committee of SRPC which is extracted as under:

(i) Intermittency of wind generation vis a vis requirement not to change

drawal by more than 100 MW was a huge challenge.

(ii) Overlapping of four groups of interruptible loads was inevitable.

(iii) Implementation of GSES in Southern Region was agreed in

principle.

(iv) Funding of GSES requested to be carried out through PSDF.

(v) Detailed engineering of GSES to be done in consultation with the

States for Finalization of BoQ.

(vi) SLDC should have over riding powers to decide the feeders etc.

15. Southern Regional Load Despatch Centre vide its affidavit dated 4.12.013

has submitted as under:

(a) All the SLDC’s including APTRANSCO have declared grouping of loads

as per clause 5.4.2 (e) of the Grid Code. It is also confirmed that the SLDC has

the provision to trip the feeder from SLDC, SCADA. However, the required


action of demand side management has been effected only with the

intervention of Shift in-charge Engineer. This leads to delay in decision making

by the Control Engineers of SLDCs. Though four groups were declared by the

constituents, the quantum declared on each feeder widely varies with the

declared quantum thereby impacting the safety-net adversely. This

necessitates identification of additional feeders so as the average load

available for relief during contingencies is equivalent to specified value as per

system studies.

(b) UI for the day indicated is net of positive and negative deviations with

respect to schedule of the constituent. However, there are numerous occasions

in which the change in drawal was more than 100 MW violating the Regulation

5.2 (j) of the Grid Code.

(c) Subsequently, the portion of GSES pertaining to SR was presented as one

of the agenda item by SRLDC in the 76th OCC meeting of SRPC held on

11.10.2012. The same was also emphasized in the 16th PCC meeting of SRPC

held on 6.11.2012. Feedback / action plan in this regard are yet to be received

from the SR constituents. Being an issue of protection / defense plan, the

association of SRPC with necessary lead is essential for implementation.


16. Views of utilities on Grid Security Expert System (GSES) dated 1.3.2013

are as under:

(a) Generating companies as well as SLDCs were not in favour of

automatic generation reduction.

(b) POSOCO clarified that in case reduction in generation is required,

only annunciation will be given in generating station’s control room and

operator will manually reduce generation. Some of the constituents were of

the view that same can be achieved through message and there was no need

for GSES for this purpose.

(c) Automatic Demand Management System and GSES were similar.

Implementing both the schemes independently would lead to duplication and

avoidable expenditure.

(d) Some of the constituents were of the view that if load shedding is

carried out through GSES, a distribution company which was complying with

intra-State schedule may get affected.

(e) NTPC maintained that the suggestion regarding over injection by

generating company and under drawal by State utilities in POSCO report is

not in consonance with CERC Regulations.


(f) Delhi Discoms opined that there is need to improve the compliance

and maintaining the existing system instead of creating a new grid security

system with huge expenditure.

(g) Some of constituents were of the opinion that some of the modules

of GSES viz. UFR, df/dt, Islanding Schemes are part of the existing system.

These is a need to dovetail these is the GSES.

17. During the course of hearing on 7.3.2013, the representative of NRLDC

submitted that Automatic Demand Management Scheme within the State control

areas is an essential as by their own admission States have indicated time taken

as high as 40-45 minutes in taking corrective action through manual means. Since

these automatic schemes are not available, it becomes very difficult for States to

control overdrawal in case there are very high overdrawals. The representative of

NRLDC further submitted that as per Commission`s direction, NRLDC is resorting

to opening of feeders of States on certain occasions. However, opening of feeders

at 220 kV and 400 kV level from NRLDC may be indiscriminate and can impact

some of the essential loads in the States as well. At EHV levels many lines are

not radial in nature which affects quantum as well as area of impact due to such

opening of lines. Thus, it is required that State’s drawal is as per schedule which

had also been emphasized by the Commission through its various

Regulations/orders and Statement of the Reasons. The representative of SRLDC

submitted that the present mechanism available for Demand Side Management


in all SLDCs control areas is manual. The constituents need to manage the

demand even at frequency above 49.8 Hz. Learned counsel for the SLDC,

Karnataka submitted that the implementation of UFR scheme, df/dt scheme and

special protection schemes are already in place. As per Regulation 5.4.2 (d) of

the Grid Code, Automatic Load Management Scheme has been implemented from

July, 2012.

18. We have considered the submissions of petitioner and respondents. We

agree to the contentions of petitioner and emphasize that Grid Security is of

utmost importance and priority.

19. From the records available, it is evident that only DTL, RRVPNL, PSPCL,

APRTRANSCO, TANTRANSCO, KSEB, KPTCL, NRPC, SRPC and SRLDC have

submitted their replies. Other respondents have not filed any response to our

order dated 14.1.2013. We do not approve of the conduct of the respondents in

not filing their response to the directions of the Commission in such a grave matter

as grid security. We direct the respondents to ensure that our directions are duly

complied with in future.

20. With regards to prayer (a): We direct all the STUs/SLDCs of the Northern

Region, Southern Region and Eastern Region to forecast their demand and make

adequate arrangements to avoid dependence on Unscheduled Interchange for


meeting their demand or for injecting short term surplus power, irrespective of the

frequency.

21. With Regards to prayer (b): The issue regarding implementation of

Automatic Demand Management Scheme will be dealt with in order in Petition No.

208/SM/2011.

22. Regarding Prayer (c): Regulation 5.2 (j) of the Grid Code provides as

under:

"5.2 (j) Except under an emergency, or to prevent an imminent damage to a costly equipment, no User shall suddenly reduce his generating unit output by more than one hundred (100) MW (20 MW in case of NER) without prior intimation to Similarly, no User / SEB shall cause a sudden variation in its load by more than one hundred (100 MW) without prior intimation and consent of the RLDC, particularly when frequency is falling or is below 49.7 Hz. Similarly, no User / SEB shall cause a sudden variation in its load by more than one hundred (100 MW) without prior intimation to and consent of the RLDC. All users and SEBs shall ensure that temporary over voltage due to sudden load rejection and the maximum permissible values of voltage unbalance shall remain within limits specified under Central Electricity Authority (Grid Standards) Regulations, 2010."

Accordingly, we direct all STUs/SLDCs/Regional entities to comply with

Regulation 5.2 (j) of the Grid Code failing which appropriate proceedings shall be

initiated against them for non-compliance with the provisions of the Grid Code and

directions of the Commission.


23. Regarding Prayer (d): The issue of Grid Security Expert System will be

dealt with in order in Petition No. 265/MP/2012.

24. With this, Petition Nos. 249/MP/2012, 250/MP/2012 and 251/MP/2012 are

disposed of.

Sd/- sd/-

(M. Deena Dayalan) Member

(V. S. Verma) Member

Documents

CENTRAL ELECTRICITY REGULATORY …Order in Petition No. 249/250/251/MP/2012 Page 1 of 29 CENTRAL ELECTRICITY REGULATORY COMMISSION NEW DELHI Petition No. 249/MP/2012 Coram: Shri V.S.Verma,